Fix Start-OSDCloud -ZTI blocking on image index prompt with -FindImageFile

[kristofferkhansen]

Fixes #287

Problem

Start-OSDCloud -FindImageFile -ZTI still blocks on interactive prompts, defeating fully zero-touch deployments. The only known workaround is piping stdin to answer them, e.g.:

cmd /c 'echo 1 | powershell -command Start-OSDCloud -Restart -ZTI -FindImageFile -SkipAutopilot -SkipODT'

Two unguarded prompts are involved:

1. Select-OSDCloudFileWim — always prompts to pick a WIM/ESD/SWM file under \OSDCloud\OS\, even with a single candidate. On closed/EOF stdin, Read-Host returns '', and '' -ge 0 evaluates false, so the do/until loop spins forever instead of failing.
2. Select-OSDCloudImageIndex — always prompts to pick an image index whenever the selected WIM contains more than one image.

Fix

• Select-OSDCloudFileWim.ps1: add a -ZTI switch. With exactly one file candidate, auto-select it. With more than one, throw immediately rather than guessing which image to deploy or hanging on a starved prompt — picking the wrong file is worse than picking the wrong index within a file, so this deliberately does not auto-pick the first result.
• Select-OSDCloudImageIndex.ps1: add a -ZTI switch. Auto-return the first image index instead of prompting (matches the value the community echo 1 workaround was already manually supplying).
• Start-OSDCloud.ps1: pass -ZTI:$Global:StartOSDCloud.ZTI at both call sites in the -FindImageFile path.

This mirrors the existing $Global:StartOSDCloud.ZTI short-circuit pattern already used elsewhere in Start-OSDCloud.ps1 to skip prompts in ZTI mode.

Start-OSDCloudCLI.ps1's call site for Select-OSDCloudImageIndex is untouched (no -ZTI param passed), so its interactive behavior is unaffected.

Test plan

• Parser.ParseFile on all changed files — no syntax errors
• Mocked Get-WindowsImage returning 2 images: Select-OSDCloudImageIndex -ZTI returns the first index (1) with no prompt
• Mocked single-image case: unchanged short-circuit behavior (still returns without prompting)
• Mocked Find-OSDCloudFile returning 1 candidate: Select-OSDCloudFileWim -ZTI auto-selects it with no prompt
• Mocked Find-OSDCloudFile returning 2 candidates: Select-OSDCloudFileWim -ZTI throws immediately instead of hanging or guessing
• Real WinPE Start-OSDCloud -Restart -ZTI -FindImageFile -SkipAutopilot -SkipODT run against real media (not verified in this environment — no WinPE available)

After this fix, the original command works without the echo 1 stdin workaround:

Start-OSDCloud -Restart -ZTI -FindImageFile -SkipAutopilot -SkipODT

[kristofferkhansen]

Tested ok on my side.

[kristofferkhansen]

Cross-referencing #259, which addresses part of the same problem — it auto-selects the WIM in Select-OSDCloudFileWim when there's exactly one candidate, so there's been demand for unattended -FindImageFile for a while.

Differences in scope:

• Update Select-OSDCloudFileWim.ps1 #259 changes behavior for all runs (interactive included) and covers only the file prompt. A -ZTI run still blocks on Select-OSDCloudImageIndex when the selected WIM contains more than one image, and with several file candidates the prompt still hangs on closed stdin.
• This PR gates everything behind -ZTI (interactive behavior untouched), guards both prompts, and with several file candidates fails fast with a clear error instead of hanging or guessing.

If this merges, #259 could be closed as superseded.